Electroencephalography (EEG) refers to a technique for monitoring electrical activity of the brain of a living organism—typically the brain of a human subject. Fluctuations in electrical potential may be observed at various locations or regions of the brain via a set of EEG interfaces that are spatially distributed relative to the subject's head. These EEG interfaces may take the form of non-invasive electrodes that are placed near or in contact with the scalp at various locations.
An event-related potential (ERP) refers to a response of the brain to a stimulus event that has been perceived by the subject. ERPs may be detected via EEG as fluctuations in electrical potential observed during a period of time following the subject's perception of the stimulus event. With respect to human subjects, temporal fluctuations in electrical potentials observed at particular locations relative to the head of the human subject and within time-locked search windows relative to onset of the stimulus event enable such ERPs to be detected and identified.
A range of ERPs, referred to as ERP components, have been experimentally observed across large populations of human subjects in a consistent manner with respect to the type of stimulus, suggesting the universality of such ERPs in humans. Many ERP components have been characterized with respect to the type of stimulus event that elicits an observable fluctuation in electrical potential, and these fluctuations have been assigned names by the scientific community within a nomenclature that enables consistent identification and discussion of the ERP components.